There have been extensive discussions on exactly this topic at TGR. IIRC, maybe one or two here. A little time spent using search will likely provide you with the basics on some of these questions, and help frame additional questions.
The top level story is that there is great skiing and a great base at most of the Cascade areas. But microclimate is everything. Which puts a premium on flexibility. Which sort of makes it less painful that your lodging options are limited as there is virtually no on-mountain lodging anywhere in the neighborhood - with the exception of a few rooms at xtal. Consider some time spent "north" and some spent "south". if you stay north of seattle, you can look at the conditions and "easily" hit Baker or Stevens. South gives you Crystal and Summit. You;d be amazed at the microclimate effects - there are times an area can get a foot or more and north or south gets a couple inches...
Anyway, do some rooting around here and TGR and see what you think.
My guess is you can get folks to show you around a bit - but that'll be more of a real-time thing. If you come - post up then.
For my .02 - if the snow is good, you will want fat rockered skis. There is a reason you see them all over here.
